1. Field
Example embodiments of the following description relate to a power-supply circuit for a DC appliance for safely outputting a DC current when an input DC current is abruptly changed.
2. Description of the Related Art
Conventionally, power has been supplied to household appliances or electric devices of a general home by an AC power distribution system providing commercial power. The AC power distribution system supplies power to electric devices using a plug, a socket, a switch, and the like. In addition, the electric device having received AC power converts AC power into DC power using a rectifier embedded therein. Although the AC power distribution system does not include a device for preventing arc from being generated in plug separation, safety or stability is not guaranteed.
However, in the future, it is expected that the demand of a general home that desires to use DC power using a solar battery, a fuel cell, and the like. will rapidly increase. DC power can reduce energy loss generated when a conventional AC power distribution system converts AC power into DC power, and can be easily stored, so that it can effectively cope with emergencies. In the case of using AC power, provided that a unique power factor of a device is bad or poor, although the device has the same power consumption, a generation end has to generate as much power as reactive power, resulting in energy inefficiency.
In fact, the number of household appliances, each including an inverter, is rapidly increasing, and most digital devices use DC current.
Therefore, a plug suitable for DC power distribution is needed. The conventional DC power plug is identical in structure to the AC power plug, so that a rush current occurs in power distribution or an arc occurs in power distribution blocking, resulting in safety issues.
The DC current has a positive polarity and a negative polarity, differently from the AC current. If a reverse voltage is applied to an electric device, the electric device is not operated and constituent components of the power-supply unit are broken. Therefore, a plug for DC current distribution needs to be designed to make a distinction between the positive and negative polarities, and a conventional DC plug may include different sizes of an anode terminal and a cathode terminal, as shown in FIG. 1A, in such a manner that the anode terminal and the cathode terminal are differently inserted into a socket, or may include anode and cathode terminals arranged in the form of L-shape, as shown in FIG. 1B.
In conclusion, the user may have difficulty in using a DC plug capable of being inserted in one way, as compared to using the AC plug, capable of being inserted in two ways.